| 摘要 |
PURPOSE:To decide the center of a pattern with high accuracy by calculating the moment at each point of a differential signal to obtain a zero-cross point and deciding the center of a pattern. CONSTITUTION:The video signals supplied from an image pickup device 1 are sampled in a prescribed cycle and the digitized picture data is stored in a picture memory 3. These picture data are integrated at every window and every direction Y and the differential data Lb(x) is outputted from a differential device 5. A noise eliminator 6 outputs the data containing no noise signal and a moment Mx within width P0 is calculated for each point (x). A center detector 8 detects a zero-cross point from the moment Mx and decides the point (x) as the center xc of a window. The center values xc are sent to a center deciding means 9 at every window and a histogram is produced for the value xc at every window. Thus the center xc' of a mark pattern is decided. |
